In a symbolic show of anger, Canadian fans began booing the Star Spangled Banner before NHL and NBA games over the weekend. The mass protests come on the same weekend that U.S. President Donald Trump imposed 25% tariffs on imports from Canada and Mexico, as well as 10% on those from China. Trump’s announcement of tariffs was met with retaliatory measures from Canada and the promise of “tariff and non-tariff measures” from Mexico.

Typically, at NHL and NBA games involving teams from each country, both countries’ anthems are performed before play begins. During the Star Spangled Banner at NHL games in Ottawa, Vancouver and Calgary, usually-demure Canadians began loudly booing the U.S. anthem, at some points making it hard to even hear the song. The anthem does not appear to have been a part of televised coverage of the games, but attendees quickly began posting video of the moments online.